1. Field of the Invention
The invention relates to a high-pressure fuel pump with a delivery chamber that is connected on the intake side via an intake valve to a low-pressure fuel line and is connected on the pressure side via a high-pressure connection to a high-pressure fuel line, in which a check valve and a pressure relief valve connected parallel to it are provided between the delivery chamber contained in a housing and the high-pressure connection connected in a fluid-tight manner to the housing, and the pressure relief valve is contained in a blind hole bore of the housing.
2. Description of the Prior Art
A high-pressure fuel pump of the type with which this invention is concerned is known from DE 103 27 411, which was published after the priority date of the present application. The advantage of this high-pressure fuel pump is that the pressure relief valve does not open during the delivery stroke and consequently, transient pressure peaks that occur during the delivery stroke of the high-pressure fuel pump do not reduce the volumetric efficiency of the high-pressure fuel pump. Only during the intake stroke when a much lower pressure prevails in the delivery chamber than in the high-pressure fuel line does the pressure relief valve open if the high-pressure fuel line contains an impermissibly high pressure, thus effectively protecting the high-pressure fuel pump and the entire high-pressure region of the fuel injection system from impermissibly high pressures.
Another feature of the high-pressure fuel pump according to the invention is that the blind hole bore that contains the pressure relief valve starts from a chamber delimited by the high-pressure connection and the housing.